Sold in Packs of: 1 Voltage Detector, Non-Contact, 10 - 49 V, 50 - 1000 V, LED, AAA Alkaline, Automatic Cut-Off Switch, Different colors identify voltage range A built-in LED work light allows for increased visibility in low-lit areas and automatic shut-off after 5 minutes helps preserve battery life Auto-off Pocket clip Blade tip for checking outlets It does so by using a uniquely colored LED indicators and audible tones Delivering the clearest indication of these two voltage ranges The expanded sensitivity range of 10 - 49 V offers the ability to detect voltage in common systems that would normally go undetected when using a standard voltage detector These systems include LED lighting, fire detection and suppression systems, HVAC controls and security and access controls, along with many others The 10 - 1000 V dual range voltage detector not only detects, but also differentiates 10 - 49 V from the standard voltage range of 50 - 1000 V